The present invention relates to the field of wireless computer networking.
Currently, one of the newest trends in the personal computer (PC) industry involves wireless networking. Specifically, the ability to inexpensively and reliably interconnect multiple computers, peripherals, and like devices within an office or home, without having to install an Ethernet or twisted pair backbone wiring is a strongly desired goal for office and home networking device Original Equipment Manufacture (“OEM”). To achieve this goal, a variety of wireless networking solutions have been designed. These wireless computer networks typically use the radio frequency (RF) bands at 900 MHz and 2.4 GHz that were provided for this type of application.
Typical solutions for desktop computers are comprised of a Personal Computer (“PC”) card that plugs into a computer and an antenna that connects to the PC card. The antenna is then mounted onto the outside of the computer case or other convenient external object. For example, the antenna may incorporate a magnetic mount that holds the antenna onto the top of the computer chassis. Alternatively, an antenna may be attached to the computer chassis with an adhesive tape.
However, these systems suffer from at least two deficiencies. First, they are expensive to make. Having to make a separate PC card for the network increases the unit cost relative to a computer with all the circuits on the main board. Given the heavy cost constraints, all PC OEMs have, a single main board solution is highly preferable. The second deficiency relates to the antenna. An external antenna is expensive to supply to the end user. These antennae are typically manufactured by companies specializing in such devices and must be purchased by the computer OEM and packaged with the computer. This increases the logistical issues and costs for the OEM.
While putting the wireless networking components on the main board reduces the unit cost, it creates the problem of connecting an antenna to those network components. Also, as the chassis provides a shielding function “Faraday Cage” to supress electromagnetic interference (“EMI”), any cable passing through it will provide an unwanted outlet for radiation that can cause EMI. Even if the cable is shielded, such as a coaxial antenna cable, and connected to electrical ground at the main board, the impedance of the shield is such that it can still act as an effective radiator for signals generated inside the computer. Such radiation may violate the strict radiation limits imposed by the FCC on PC OEMs and prevent the computer from being sold.
There exists therefore a need for a cost effective antenna system that connects to a wireless network device internal to a computer.